As a conventional art, for example, a vibration actuator for driving a moving element by using an electromechanical conversion element has been known (Patent Document 1), in which, however, a bearing is arranged on an outer circumference, involving a problem that the sliding sound of the bearing is loud.
Meanwhile, the use of a plastic bearing has been proposed for the purpose of attenuating the sound of such a vibration actuator (Patent Document 2).
Patent Document 1: Japanese Unexamined Patent Application, Publication No. S63-103675
Patent Document 2: Japanese Unexamined Patent Application, Publication No. 2011-10539